System, method, and apparatus for voice handoffs

ABSTRACT

A power management system is described where the handset can enter sleep or hibernation mode for a particular service, when the particular service is either not used or not available. The handset is capable of using the service, even in response to a non-user initiated incoming request for communication. The handset receives the request over the active service. The handset can then check for the availability of the inactive service, activate it, and a selection can be made between them.

RELATED APPLICATIONS

This application claims priority to Application Serial No. 60/679,936filed Aug. 16, 2005 by Govindarajan, et. al. The foregoing isincorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

Wireless radio technology provides both cellular service and wirelesslocal area networks. Cellular service provides both mobile telephone anddata services, including Internet access. Wireless local area networks(wi-fi) have traditionally provided data services, as well. Thedevelopment of the transfer of voice data over a packet-based network,such as the internet, allows voice communications. This is known asVoice over IP (VOIP), which has been used as a substitute for telephoneservice.

A user can use a modern wireless handset to access both cellular serviceand wi-fi, if they are available. The availability of each of theseservices depends on the location of the user and the radio coverage foreach of these services at the user's location. When both are accessible,the user has a choice. The user can choose between the wi-fi andcellular service for both data services and between cellular phoneservice or VOIP.

The handsets scan for both cellular service and wi-fi signals. When thehandset is out of range for either service, the handset may continue toscan for a signal, or stop scanning for the out of range signal.Continuing to scan for a signal consumes the battery of the handset.

By not scanning, the handset misses opportunities when the signalbecomes available. For example, a user may travel through a hole in theradio coverage of either the cellular or wi-fi service. If when thehandset loses the signal, the handset stops scanning, the handset willmiss the signal when the user exits the hole.

This circumstance is aggravated when there is a communication attemptinitiated by another party, such as an incoming phone call, or requestfor a chat communication. If the handset is not scanning for either thecellular service, or the wi-fi service, the incoming phone call/requestfor a chat communication is not received. If the handset is accessingone of the services, for example the cellular service, the handsetreceives the communication attempt via the cellular service. This canoccur, even where the wi-fi service is available. However, handset doesnot take advantage of this choice.

BRIEF SUMMARY OF THE INVENTION

A power management system is described where the handset can enter sleepor hibernation mode for a particular service, when the particularservice is either not used or not available. The handset is capable ofusing the service, even in response to a non-user initiated incomingrequest for communication. The handset receives the request over theactive service. The handset can then check for the availability of theinactive service, activate it, and a selection can be made between them.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram of the service options for the handset;

FIG. 2 is a state diagram describing the power states of the handset;

FIG. 3 describes the signaling for emerging from the cellular on/wi-fioff state to the cellular on/wi-fi on state;

FIG. 4 is a flow diagram for emerging from the cellular on/wi-fi offstate to the cellular on/wi-fi on state by the handset;

FIG. 5 describes the signaling for emerging from the cellular off/wi-fion to the cellular on/wi-fi on state;

FIG. 6 is a flow diagram for emerging from the cellular off/wi-fi on tothe cellular on/wi-fi on state by the handset;

FIG. 7 is a flow diagram for the provider server; and

FIG. 8 is a block diagram for the handset.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram of converged networks providing service for handset100. The handset 100 has access to both a cellular network 110 and awi-fi network 120. The cellular network 110 provides both cellulartelephone and data services, such as Internet access and short messageservices (SMS) to the handset 100. The cellular network 110 isgenerally, but does not have to be, a public land mobile network (PLMN),for example, according to GSM/GPRS (Global System for MobileCommunications and General Packet Radio Services).

The cellular network 110 provides access to the public switchedtelephone network (PSTN), allowing the handset to call and be called byanother telephone. The cellular network 110 also provides access to theinternet. The handset 100 can then access web servers, conduct chatsessions, and send email using the Internet. The cellular network 110also includes a provider server 130. The provider server 130 can be acomputer that is linkable to a network.

The wi-fi network 120 also provides access to the Internet as well asother data services. The wi-fi network 120 is generally a more localizednetwork, as compared to the cellular network. For example, the wi-finetwork 120 can cover a corporate campus or the like, and also provideaccess to the company computer network.

The handset 100 can be a laptop, a palm pilot, a PDA, a blackberry,mobile phone or the like that can wirelessly access the cellular network110 and the wi-fi network 120. The handset 100 includes receivers forreceiving the radio signals from both the cellular network 110 and thewi-fi network 120. The receivers scan for signals from the cellularnetwork 110 and the wi-fi network 120.

When the handset 100 is out of range for either service, the handsetpowers down in a manner that maintains its readiness to wake up. Thispreserves battery power and saves energy. The handset 100 can be in fourdifferent power states:

a. Cellular Awake/Wi-fi Awake

b. Cellular Awake/Wi-fi Asleep

c. Cellular Asleep/Wi-fi Awake

d. Cellular Asleep/Wi-fi Asleep

FIG. 2 is a state diagram describing the power states of the handset. Instate a, the handset 100 scans for signals from both the cellularnetwork 110 and the wi-fi network 120. For a variety of reasons, thesignals that the handset 100 receives may fade. For example, the handset100 may move to an area where the signal from either of the networks isweak or non-existent.

If the signals from cellular network 110 or wi-fi network 120 fades toless than some threshold signal strength, the cellular network 110 is nolonger accessible by the handset 100. After a period of time, thehandset 100 stops scanning for a signal from the cellular network 110 orwi-fi network 120. When the handset 100 stops scanning for the signalfrom the cellular network 110, the handset 100 enters state c (arrow205). When the handset 100 stops scanning for the signal from the wi-finetwork 120, the handset enters state b (arrow 210). From states b andc, where the handset 100 stops scanning for the signal from the othernetwork 110, or 120, the handset 100 enters state d (arrow 215). Instate d, the handset 100 polls the services at regular time intervals.Although the handset 100 stops scanning in states b, c, and d, thehandset 100 is ready to resume both cellular 110 and wi-fi services 120where such services are available. The existence of certain conditionscause the handset 100 to check for the availability of a particularservice. Where the particular service is found, the handset 100 changesstates.

FIG. 3 is a signal diagram for emerging from the cellular on/wi-fi offstate to the cellular on/wi-fi on state as shown in FIG. 2, arrow 220.The handset 100 maintains access to the cellular services 110, but doesnot scan for signals from the wi-fi service 120.

The handset 100 checks for the availability of the wi-fi service 120responsive to a variety of conditions. Some of the conditions may beuser-initiated. Examples of user-initiated conditions are placement ofan outbound call, initiation of a chat request, accessing a web page, orsending an email. When one of these conditions occur, the handset 100polls (arrow 305) for a wi-fi signal.

If the wi-fi signal is available, the handset 100 establishes a wi-ficonnection (arrow 310). Upon establishing the wi-fi connection, thehandset 100 transmits a signal (arrow 315) that informs the providerserver 130 of its access to wi-fi services 120 over the wi-fi network.The signal provides information, such as the handset 100 IP address, andother information, such as user preferences, signal strength of thewi-fi, and the amount of battery power for the handset 100.

If the wi-fi signal is available, the handset 100 compares the cellularservice 110 to the wi-fi service 120 according to certain metrics. Thesemetrics include (but are not limited to):

-   -   a. Costs—the cost of each of the services. The cheaper service        is preferred.    -   b. Power Consumption—the amount of power consumed by each        service. The less power hungry service is preferred.    -   c. Quality of Services—how suitable the service is for the        communication.    -   d. Signal Strength—the strength of the signal received.    -   e. User Preferences        Based on the comparison of a combination of these metrics, the        handset 100 selects between the cellular service 110 and the        wi-fi service 120. For the data services, such as chat request,        web page access, or sending an email, the handset 100 can use        either the cellular service 110 (arrow 320) or the wi-fi service        120 (arrow 325) to access the Internet. For the outgoing call,        the handset 100 can either use the wi-fi service for VOIP, or        the cellular service 110.

The handset 100 also checks for the availability of the wi-fi services120 in response to non-user initiated events. These events can include,for example, an incoming phone call, email, or chat request. Theprovider server 130 receives the incoming communication, and routes thecommunication through the cellular network 110 to the handset 100. Thecellular network 110 transmits a control signal (arrow 330) to thehandset 100.

The handset 100 polls the wi-fi network 120 (arrow 305) to determine ifwi-fi services are available. If the wi-fi services 120 are available,the handset 100 registers with the wi-fi services 120. Additionally, thehandset 100 sends a signal (arrow 315) over the wi-fi network 120 to theprovider server 130, informing the provider server 130 of its IPaddress, and other information.

The handset 100 or provider server 130 compares the cellular service 110and the wi-fi service 120 according to the aforementioned metrics andselects either the cellular network 110 or the wi-fi service 120 andselects one. If the handset 100 selects the service, the handset 100sends a selection signal (arrow 315) to the provider server 130. Theprovider server 130 can route the communication through the cellularnetwork 110 (signal 325) or the wi-fi network 120 (signal 320).

Referring now to FIG. 4, there is illustrated a flow diagram foremerging from the cellular on/wi-off state to the cellular on/wi-fi onstate by the handset 100. At 405, an event occurs at the handset 100.The event can either be receiving a command for a user-initiated action,or receiving a notification of a non-user initiated communication. Uponthe occurrence of the event, at 410 the handset 100 polls the wi-fiservice 120. If at 415, the wi-fi service is available, the handset 100registers with the wi-fi service at 420, notifies the provider server130 at 425, and compares the cellular service 110 to the wi-fi service120 according to the certain metrics at 430. At 435, the handset 100communicates using the selected service. If at 415, the wi-fi service isunavailable, the handset communicates using the cellular service 110 at440.

FIG. 5 is a signal diagram for emerging from the cellular off/wi-fi onstate to the cellular on/wi-fi on state as shown in FIG. 2, arrow 230.The handset 100 maintains access to the wi-fi services 120, but does notscan for signals from the cellular services 110. When the handset 100accesses the wi-fi services 120, the handset 100 sends a notification(502) to the provider server 130. The notification 502 includes the IPaddress for the handset 100, and other information, such as userpreferences, signal strength of the wi-fi, and the amount of batterypower for the handset 100.

The handset 100 checks for the availability of the cellular service 110responsive to a variety of conditions. Some of the conditions may beuser-initiated. Examples of user-initiated conditions are placement ofan outbound call, initiation of a chat request, accessing a web page, orsending an email. When one of these conditions occur, the handset 100polls (arrow 505) for a cellular signal.

If the cellular signal is available, the handset 100 establishes aconnection (arrow 510) with the cellular network 110. If the cellularsignal is available, the handset 100 compares the cellular service 110to the wi-fi service 120 according to certain metrics.

Based on the comparison of a combination of these metrics, the handset100 selects between the cellular service 110 and the wi-fi service 120.For the data services, such as chat request, web page access, or sendingan email, the handset 100 can use either the cellular service 110 (arrow520) or the wi-fi service 120 (arrow 525) to access the Internet. For anoutgoing call, the handset 100 can either use the wi-fi service 120 forVOIP, or the cellular service 110.

The handset 100 also checks for the availability of the cellularservices 110 in response to non-user initiated events. These events caninclude, for example, an incoming phone call, email, or chat request.The provider server 130 receives the incoming communication, and routesthe communication through the wi-fi network 120 to the handset 100. Asnoted above, the provider server 130 is aware of the handset 100 IPaddress from signal 502. The wi-fi network 120 transmits a controlsignal (arrow 530) to the handset 100, informing the handset 100 of theincoming communication.

The handset 100 polls the cellular network 110 (arrow 505) to determineif cellular services 110 are available. If the cellular services 110 areavailable, the handset 100 registers with the cellular services 110. Theprovider server 130 compares the cellular service 110 and the wi-fiservice 120, using the information provided to it from signal 502,according to the metrics and selects either the cellular network 110 orthe wi-fi service 120. Alternatively, the handset 100 makes thecomparison and selection, and informs the provider server. The providerserver 130 can route the communication through the cellular network 110(arrow 540) or the wi-fi network 120 (arrow 550).

Referring now to FIG. 6, there is illustrated a flow diagram foremerging from the cellular on/wi-off state to the cellular on/wi-fi onstate by the handset 100. At 605, an event occurs at the handset 100.The event can either be receiving a command for a user-initiated action,or receiving a notification of a non-user initiated communication. Uponthe occurrence of the event, at 610 the handset 100 polls the cellularservice 110. If at 615, the cellular service 110 is available, thehandset 100 registers with the cellular service at 620, notifies theprovider server 130 at 625, and compares the cellular service 110 to thewi-fi service 120 according to the certain metrics at 630. At 635, thehandset 100 communicates using the selected service. If at 615, thecellular service 110 is not available, the handset 100 communicatesusing the wi-fi service at 640.

Referring now to FIG. 7, there is illustrated a flow diagram for theprovider server 130. At 705, the provider server 130 receives anincoming communication request. At 710, the provider server 130 attemptsto locate the handset 100 in both the cellular network 110 and the wi-finetwork 120.

If the handset 100 at 715 is only available in one of the networks, theprovider server 130 notifies the handset 100 in the available network ofthe incoming request for communication. At 720 the provider server 130receives a notification from the handset 100 indicating whether thehandset 100 was able to establish connection with the other network, andif so, its location in the other network. At 725, the provider 130receives a signal from the handset 100 indicating the preferred network.At 730, the provider server 130 sends the incoming request forcommunication to the handset 100 over the selected network.

FIG. 8 is a block diagram of the handset 100. The handset 100 includesreceiver(s) Rx for receiving radio signals from the cellular service 110and the wi-fi service 120, transmitter(s) Tx for transmitting radiosignals to the cellular service 110 and the wi-fi service 120, akeyboard 825, a microphone 830, speaker 835, processor 840, a memory845, a screen 847, and a battery 850. The memory 845 can store softwarethat is run by the processor 840 that controls the handset 100 as hasbeen described.

The foregoing section and figures describe the present invention by wayof example. The present invention is not limited by the foregoingexamples. Although cellular and wi-fi services are used as examples,other services can also be used. The examples can be modified in avariety of ways without departing from the scope of the presentinvention. Therefore, the present invention includes all embodimentsfalling within the scope of the following claims.

1. A method for selecting a service, said method comprising: receivingan event; determining if one type of service is available; registeringthe one type of service; comparing the one type of service with a secondtype of service; selecting between the one type of service and thesecond type of service; responding to the event using the selected typeof service.
 2. The method of claim 1, wherein the event is a userinitiated event.
 3. The method of claim 1, wherein the event is anincoming request for communication.
 4. The method of claim 1, where theone type of service is cellular service.
 5. The method of claim 1, wherethe second type of service is wi-fi service.
 6. The method of claim 1,where the one type of service is wi-fi service.
 7. The method of claim1, where the second type of service is cellular service.
 8. A method forrouting an incoming request for a communication, said method comprising:receiving the incoming request for the communication; locating thereceiving handset in one network; alerting the receiving handset overthe one network; receiving a signal from the handset indicating to sendthe request for the communication over a selected network; sending therequest for the communication over the selected network.
 9. The methodof claim 8, wherein the one network is a cellular network, and theselected network is a wi-fi network.
 10. The method of claim 8, whereinthe one network is a cellular network and the selected network is thecellular network.
 11. The method of claim 8, wherein the one network isa wi-fi network, and the selected network is a cellular network.
 12. Themethod of claim 8, wherein the one network is a wi-fi network and theselected network is the wi-fi network.